Merge "[zmq] Implement retries for unacknowledged CASTs"

28 files changed, 860 insertions, 168 deletions

diff --git a/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_base.py b/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_base.py
index 4a5eba4..3c232e3 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_base.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_base.py
@@ -16,12 +16,11 @@ import abc
 from concurrent import futures
 import logging
 
-import retrying
-
 import oslo_messaging
 from oslo_messaging._drivers import common as rpc_common
 from oslo_messaging._drivers.zmq_driver.client.publishers \
     import zmq_publisher_base
+from oslo_messaging._drivers.zmq_driver.client import zmq_response
 from oslo_messaging._drivers.zmq_driver.client import zmq_sockets_manager
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
@@ -56,15 +55,13 @@ class DealerPublisherBase(zmq_publisher_base.PublisherBase):
             {"tout": request.timeout, "msg_id": request.message_id}
         )
 
-    @abc.abstractmethod
-    def _connect_socket(self, request):
-        pass
-
     def _recv_reply(self, request):
-        reply_future, = self.receiver.track_request(request)
+        reply_future = \
+            self.receiver.track_request(request)[zmq_names.REPLY_TYPE]
 
         try:
             _, reply = reply_future.result(timeout=request.timeout)
+            assert isinstance(reply, zmq_response.Reply), "Reply expected!"
         except AssertionError:
             LOG.error(_LE("Message format error in reply for %s"),
                       request.message_id)
@@ -84,9 +81,8 @@ class DealerPublisherBase(zmq_publisher_base.PublisherBase):
     def send_call(self, request):
         self._check_pattern(request, zmq_names.CALL_TYPE)
 
-        try:
-            socket = self._connect_socket(request)
-        except retrying.RetryError:
+        socket = self.connect_socket(request)
+        if not socket:
             self._raise_timeout(request)
 
         self.sender.send(socket, request)
diff --git a/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_direct.py b/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_direct.py
index 56d8b49..f6d3040 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_direct.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_direct.py
@@ -33,17 +33,22 @@ class DealerPublisherDirect(zmq_dealer_publisher_base.DealerPublisherBase):
 
     def __init__(self, conf, matchmaker):
         sender = zmq_senders.RequestSenderDirect(conf)
-        receiver = zmq_receivers.ReplyReceiverDirect(conf)
+        if conf.oslo_messaging_zmq.rpc_use_acks:
+            receiver = zmq_receivers.AckAndReplyReceiverDirect(conf)
+        else:
+            receiver = zmq_receivers.ReplyReceiverDirect(conf)
         super(DealerPublisherDirect, self).__init__(conf, matchmaker, sender,
                                                     receiver)
 
-    def _connect_socket(self, request):
-        return self.sockets_manager.get_socket(request.target)
-
-    def _send_non_blocking(self, request):
+    def connect_socket(self, request):
         try:
-            socket = self._connect_socket(request)
+            return self.sockets_manager.get_socket(request.target)
         except retrying.RetryError:
+            return None
+
+    def _send_non_blocking(self, request):
+        socket = self.connect_socket(request)
+        if not socket:
             return
 
         if request.msg_type in zmq_names.MULTISEND_TYPES:
diff --git a/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_proxy.py b/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_proxy.py
index fb10ce7..e6862b8 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_proxy.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/publishers/dealer/zmq_dealer_publisher_proxy.py
@@ -36,7 +36,10 @@ class DealerPublisherProxy(zmq_dealer_publisher_base.DealerPublisherBase):
 
     def __init__(self, conf, matchmaker):
         sender = zmq_senders.RequestSenderProxy(conf)
-        receiver = zmq_receivers.ReplyReceiverProxy(conf)
+        if conf.oslo_messaging_zmq.rpc_use_acks:
+            receiver = zmq_receivers.AckAndReplyReceiverProxy(conf)
+        else:
+            receiver = zmq_receivers.ReplyReceiverProxy(conf)
         super(DealerPublisherProxy, self).__init__(conf, matchmaker, sender,
                                                    receiver)
         self.socket = self.sockets_manager.get_socket_to_publishers()
@@ -45,7 +48,7 @@ class DealerPublisherProxy(zmq_dealer_publisher_base.DealerPublisherBase):
         self.connection_updater = \
             PublisherConnectionUpdater(self.conf, self.matchmaker, self.socket)
 
-    def _connect_socket(self, request):
+    def connect_socket(self, request):
         return self.socket
 
     def send_call(self, request):
diff --git a/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py b/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py
index 9da0c05..8c6c100 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py
@@ -73,6 +73,12 @@ class PublisherBase(object):
         self.receiver = receiver
 
     @abc.abstractmethod
+    def connect_socket(self, request):
+        """Get connected socket ready for sending given request
+        or None otherwise (i.e. if connection can't be established).
+        """
+
+    @abc.abstractmethod
     def send_call(self, request):
         pass
 
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_ack_manager.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_ack_manager.py
new file mode 100644
index 0000000..01bbc35
--- /dev/null
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_ack_manager.py
@@ -0,0 +1,111 @@
+#    Copyright 2016 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from concurrent import futures
+import logging
+
+from oslo_messaging._drivers.zmq_driver import zmq_async
+from oslo_messaging._drivers.zmq_driver import zmq_names
+from oslo_messaging._i18n import _LE, _LW
+
+LOG = logging.getLogger(__name__)
+
+zmq = zmq_async.import_zmq()
+
+
+class AckManagerBase(object):
+
+    def __init__(self, publisher):
+        self.publisher = publisher
+        self.conf = publisher.conf
+        self.sender = publisher.sender
+        self.receiver = publisher.receiver
+
+    def send_call(self, request):
+        return self.publisher.send_call(request)
+
+    def send_cast(self, request):
+        self.publisher.send_cast(request)
+
+    def send_fanout(self, request):
+        self.publisher.send_fanout(request)
+
+    def send_notify(self, request):
+        self.publisher.send_notify(request)
+
+    def cleanup(self):
+        self.publisher.cleanup()
+
+
+class AckManagerDirect(AckManagerBase):
+    pass
+
+
+class AckManagerProxy(AckManagerBase):
+
+    def __init__(self, publisher):
+        super(AckManagerProxy, self).__init__(publisher)
+        self._pool = zmq_async.get_pool(
+            size=self.conf.oslo_messaging_zmq.rpc_thread_pool_size
+        )
+
+    def _wait_for_ack(self, ack_future):
+        request, socket = ack_future.args
+        retries = \
+            request.retry or self.conf.oslo_messaging_zmq.rpc_retry_attempts
+        timeout = self.conf.oslo_messaging_zmq.rpc_ack_timeout_base
+
+        done = False
+        while not done:
+            try:
+                reply_id, response = ack_future.result(timeout=timeout)
+                done = True
+                assert response is None, "Ack expected!"
+                assert reply_id == request.routing_key, \
+                    "Ack from recipient expected!"
+            except AssertionError:
+                LOG.error(_LE("Message format error in ack for %s"),
+                          request.message_id)
+            except futures.TimeoutError:
+                LOG.warning(_LW("No ack received within %(tout)s seconds "
+                                "for %(msg_id)s"),
+                            {"tout": timeout,
+                             "msg_id": request.message_id})
+                if retries is None or retries != 0:
+                    if retries is not None and retries > 0:
+                        retries -= 1
+                    self.sender.send(socket, request)
+                    timeout *= \
+                        self.conf.oslo_messaging_zmq.rpc_ack_timeout_multiplier
+                else:
+                    LOG.warning(_LW("Exhausted number of retries for %s"),
+                                request.message_id)
+                    done = True
+
+        self.receiver.untrack_request(request)
+
+    def _get_ack_future(self, request):
+        socket = self.publisher.connect_socket(request)
+        self.receiver.register_socket(socket)
+        ack_future = self.receiver.track_request(request)[zmq_names.ACK_TYPE]
+        ack_future.args = request, socket
+        return ack_future
+
+    def send_cast(self, request):
+        self.publisher.send_cast(request)
+        self._pool.submit(self._wait_for_ack, self._get_ack_future(request))
+
+    def cleanup(self):
+        self._pool.shutdown(wait=True)
+        super(AckManagerProxy, self).cleanup()
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_client.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_client.py
index 0ec27e9..24f08f0 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_client.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_client.py
@@ -18,6 +18,7 @@ from oslo_messaging._drivers.zmq_driver.client.publishers.dealer \
     import zmq_dealer_publisher_direct
 from oslo_messaging._drivers.zmq_driver.client.publishers.dealer \
     import zmq_dealer_publisher_proxy
+from oslo_messaging._drivers.zmq_driver.client import zmq_ack_manager
 from oslo_messaging._drivers.zmq_driver.client import zmq_client_base
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
@@ -43,11 +44,17 @@ class ZmqClientMixDirectPubSub(zmq_client_base.ZmqClientBase):
                 conf.oslo_messaging_zmq.use_pub_sub:
             raise WrongClientException()
 
-        publisher_direct = \
-            zmq_dealer_publisher_direct.DealerPublisherDirect(conf, matchmaker)
+        publisher_direct = self.create_publisher(
+            conf, matchmaker,
+            zmq_dealer_publisher_direct.DealerPublisherDirect,
+            zmq_ack_manager.AckManagerDirect
+        )
 
-        publisher_proxy = \
-            zmq_dealer_publisher_proxy.DealerPublisherProxy(conf, matchmaker)
+        publisher_proxy = self.create_publisher(
+            conf, matchmaker,
+            zmq_dealer_publisher_proxy.DealerPublisherProxy,
+            zmq_ack_manager.AckManagerProxy
+        )
 
         super(ZmqClientMixDirectPubSub, self).__init__(
             conf, matchmaker, allowed_remote_exmods,
@@ -73,8 +80,11 @@ class ZmqClientDirect(zmq_client_base.ZmqClientBase):
                 conf.oslo_messaging_zmq.use_router_proxy:
             raise WrongClientException()
 
-        publisher = \
-            zmq_dealer_publisher_direct.DealerPublisherDirect(conf, matchmaker)
+        publisher = self.create_publisher(
+            conf, matchmaker,
+            zmq_dealer_publisher_direct.DealerPublisherDirect,
+            zmq_ack_manager.AckManagerDirect
+        )
 
         super(ZmqClientDirect, self).__init__(
             conf, matchmaker, allowed_remote_exmods,
@@ -97,8 +107,11 @@ class ZmqClientProxy(zmq_client_base.ZmqClientBase):
         if not conf.oslo_messaging_zmq.use_router_proxy:
             raise WrongClientException()
 
-        publisher = \
-            zmq_dealer_publisher_proxy.DealerPublisherProxy(conf, matchmaker)
+        publisher = self.create_publisher(
+            conf, matchmaker,
+            zmq_dealer_publisher_proxy.DealerPublisherProxy,
+            zmq_ack_manager.AckManagerProxy
+        )
 
         super(ZmqClientProxy, self).__init__(
             conf, matchmaker, allowed_remote_exmods,
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_client_base.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_client_base.py
index 4643ff3..5d6ee5a 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_client_base.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_client_base.py
@@ -37,6 +37,13 @@ class ZmqClientBase(object):
         self.notify_publisher = publishers.get(zmq_names.NOTIFY_TYPE,
                                                publishers["default"])
 
+    @staticmethod
+    def create_publisher(conf, matchmaker, publisher_cls, ack_manager_cls):
+        publisher = publisher_cls(conf, matchmaker)
+        if conf.oslo_messaging_zmq.rpc_use_acks:
+            publisher = ack_manager_cls(publisher)
+        return publisher
+
     def send_call(self, target, context, message, timeout=None, retry=None):
         request = zmq_request.CallRequest(
             target, context=context, message=message, retry=retry,
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py
index 96ebead..9f7aeec 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_receivers.py
@@ -42,12 +42,16 @@ class ReceiverBase(object):
 
     @abc.abstractproperty
     def message_types(self):
-        """A list of supported incoming response types."""
+        """A set of supported incoming response types."""
 
     def register_socket(self, socket):
         """Register a socket for receiving data."""
         self._poller.register(socket, recv_method=self.recv_response)
 
+    def unregister_socket(self, socket):
+        """Unregister a socket from receiving data."""
+        self._poller.unregister(socket)
+
     @abc.abstractmethod
     def recv_response(self, socket):
         """Receive a response and return a tuple of the form
@@ -56,13 +60,13 @@ class ReceiverBase(object):
 
     def track_request(self, request):
         """Track a request via already registered sockets and return
-        a list of futures for monitoring all types of responses.
+        a dict of futures for monitoring all types of responses.
         """
-        futures = []
+        futures = {}
         for message_type in self.message_types:
             future = futurist.Future()
             self._set_future(request.message_id, message_type, future)
-            futures.append(future)
+            futures[message_type] = future
         return futures
 
     def untrack_request(self, request):
@@ -102,14 +106,9 @@ class ReceiverBase(object):
             future.set_result((reply_id, response))
 
 
-class AckReceiver(ReceiverBase):
-
-    message_types = (zmq_names.ACK_TYPE,)
-
-
 class ReplyReceiver(ReceiverBase):
 
-    message_types = (zmq_names.REPLY_TYPE,)
+    message_types = {zmq_names.REPLY_TYPE}
 
 
 class ReplyReceiverProxy(ReplyReceiver):
@@ -121,11 +120,12 @@ class ReplyReceiverProxy(ReplyReceiver):
         assert reply_id is not None, "Reply ID expected!"
         message_type = int(socket.recv())
         assert message_type == zmq_names.REPLY_TYPE, "Reply expected!"
-        message_id = socket.recv()
-        raw_reply = socket.recv_loaded()
-        assert isinstance(raw_reply, dict), "Dict expected!"
-        reply = zmq_response.Response(**raw_reply)
-        LOG.debug("Received reply for %s", message_id)
+        message_id = socket.recv_string()
+        reply_body, failure = socket.recv_loaded()
+        reply = zmq_response.Reply(
+            message_id=message_id, reply_id=reply_id,
+            reply_body=reply_body, failure=failure
+        )
         return reply_id, message_type, message_id, reply
 
 
@@ -136,11 +136,45 @@ class ReplyReceiverDirect(ReplyReceiver):
         assert empty == b'', "Empty expected!"
         raw_reply = socket.recv_loaded()
         assert isinstance(raw_reply, dict), "Dict expected!"
-        reply = zmq_response.Response(**raw_reply)
-        LOG.debug("Received reply for %s", reply.message_id)
+        reply = zmq_response.Reply(**raw_reply)
         return reply.reply_id, reply.msg_type, reply.message_id, reply
 
 
 class AckAndReplyReceiver(ReceiverBase):
 
-    message_types = (zmq_names.ACK_TYPE, zmq_names.REPLY_TYPE)
+    message_types = {zmq_names.ACK_TYPE, zmq_names.REPLY_TYPE}
+
+
+class AckAndReplyReceiverProxy(AckAndReplyReceiver):
+
+    def recv_response(self, socket):
+        empty = socket.recv()
+        assert empty == b'', "Empty expected!"
+        reply_id = socket.recv()
+        assert reply_id is not None, "Reply ID expected!"
+        message_type = int(socket.recv())
+        assert message_type in (zmq_names.ACK_TYPE, zmq_names.REPLY_TYPE), \
+            "Ack or reply expected!"
+        message_id = socket.recv_string()
+        if message_type == zmq_names.REPLY_TYPE:
+            reply_body, failure = socket.recv_loaded()
+            reply = zmq_response.Reply(
+                message_id=message_id, reply_id=reply_id,
+                reply_body=reply_body, failure=failure
+            )
+            response = reply
+        else:
+            response = None
+        return reply_id, message_type, message_id, response
+
+
+class AckAndReplyReceiverDirect(AckAndReplyReceiver):
+
+    def recv_response(self, socket):
+        # acks are not supported yet
+        empty = socket.recv()
+        assert empty == b'', "Empty expected!"
+        raw_reply = socket.recv_loaded()
+        assert isinstance(raw_reply, dict), "Dict expected!"
+        reply = zmq_response.Reply(**raw_reply)
+        return reply.reply_id, reply.msg_type, reply.message_id, reply
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py
index 35c38a8..ab452de 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_response.py
@@ -12,23 +12,24 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import abc
+
+import six
+
 from oslo_messaging._drivers.zmq_driver import zmq_names
 
 
+@six.add_metaclass(abc.ABCMeta)
 class Response(object):
 
-    def __init__(self, msg_type=None, message_id=None,
-                 reply_id=None, reply_body=None, failure=None):
+    def __init__(self, message_id=None, reply_id=None):
 
-        self._msg_type = msg_type
         self._message_id = message_id
         self._reply_id = reply_id
-        self._reply_body = reply_body
-        self._failure = failure
 
-    @property
+    @abc.abstractproperty
     def msg_type(self):
-        return self._msg_type
+        pass
 
     @property
     def message_id(self):
@@ -38,6 +39,29 @@ class Response(object):
     def reply_id(self):
         return self._reply_id
 
+    def to_dict(self):
+        return {zmq_names.FIELD_MSG_ID: self._message_id,
+                zmq_names.FIELD_REPLY_ID: self._reply_id}
+
+    def __str__(self):
+        return str(self.to_dict())
+
+
+class Ack(Response):
+
+    msg_type = zmq_names.ACK_TYPE
+
+
+class Reply(Response):
+
+    msg_type = zmq_names.REPLY_TYPE
+
+    def __init__(self, message_id=None, reply_id=None, reply_body=None,
+                 failure=None):
+        super(Reply, self).__init__(message_id, reply_id)
+        self._reply_body = reply_body
+        self._failure = failure
+
     @property
     def reply_body(self):
         return self._reply_body
@@ -47,11 +71,7 @@ class Response(object):
         return self._failure
 
     def to_dict(self):
-        return {zmq_names.FIELD_MSG_TYPE: self._msg_type,
-                zmq_names.FIELD_MSG_ID: self._message_id,
-                zmq_names.FIELD_REPLY_ID: self._reply_id,
-                zmq_names.FIELD_REPLY_BODY: self._reply_body,
-                zmq_names.FIELD_FAILURE: self._failure}
-
-    def __str__(self):
-        return str(self.to_dict())
+        dict_ = super(Reply, self).to_dict()
+        dict_.update({zmq_names.FIELD_REPLY_BODY: self._reply_body,
+                      zmq_names.FIELD_FAILURE: self._failure})
+        return dict_
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_routing_table.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_routing_table.py
index 16de0bc..d0b6227 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_routing_table.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_routing_table.py
@@ -35,12 +35,12 @@ class RoutingTable(object):
 
     def get_all_hosts(self, target):
         self._update_routing_table(target)
-        return list(self.routable_hosts.get(str(target)) or [])
+        return list(self.routable_hosts.get(str(target), []))
 
     def get_routable_host(self, target):
         self._update_routing_table(target)
         hosts_for_target = self.routable_hosts[str(target)]
-        host = hosts_for_target.pop(0)
+        host = hosts_for_target.pop()
         if not hosts_for_target:
             self._renew_routable_hosts(target)
         return host
diff --git a/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py b/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py
index 3b83d9a..dd992e0 100644
--- a/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py
+++ b/oslo_messaging/_drivers/zmq_driver/client/zmq_senders.py
@@ -41,19 +41,22 @@ class RequestSender(SenderBase):
     pass
 
 
+class AckSender(SenderBase):
+    pass
+
+
 class ReplySender(SenderBase):
     pass
 
 
-class RequestSenderProxy(RequestSender):
+class RequestSenderProxy(SenderBase):
 
     def send(self, socket, request):
         socket.send(b'', zmq.SNDMORE)
         socket.send(six.b(str(request.msg_type)), zmq.SNDMORE)
-        socket.send(six.b(request.routing_key), zmq.SNDMORE)
-        socket.send(six.b(request.message_id), zmq.SNDMORE)
-        socket.send_dumped(request.context, zmq.SNDMORE)
-        socket.send_dumped(request.message)
+        socket.send(request.routing_key, zmq.SNDMORE)
+        socket.send_string(request.message_id, zmq.SNDMORE)
+        socket.send_dumped([request.context, request.message])
 
         LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s message "
                   "%(msg_id)s to target %(target)s",
@@ -63,28 +66,46 @@ class RequestSenderProxy(RequestSender):
                    "target": request.target})
 
 
-class ReplySenderProxy(ReplySender):
+class AckSenderProxy(AckSender):
 
-    def send(self, socket, reply):
-        LOG.debug("Replying to %s", reply.message_id)
+    def send(self, socket, ack):
+        assert ack.msg_type == zmq_names.ACK_TYPE, "Ack expected!"
+
+        socket.send(b'', zmq.SNDMORE)
+        socket.send(six.b(str(ack.msg_type)), zmq.SNDMORE)
+        socket.send(ack.reply_id, zmq.SNDMORE)
+        socket.send_string(ack.message_id)
+
+        LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s for %(msg_id)s",
+                  {"addr": list(socket.connections),
+                   "msg_type": zmq_names.message_type_str(ack.msg_type),
+                   "msg_id": ack.message_id})
+
+
+class ReplySenderProxy(SenderBase):
 
+    def send(self, socket, reply):
         assert reply.msg_type == zmq_names.REPLY_TYPE, "Reply expected!"
 
         socket.send(b'', zmq.SNDMORE)
         socket.send(six.b(str(reply.msg_type)), zmq.SNDMORE)
         socket.send(reply.reply_id, zmq.SNDMORE)
-        socket.send(reply.message_id, zmq.SNDMORE)
-        socket.send_dumped(reply.to_dict())
+        socket.send_string(reply.message_id, zmq.SNDMORE)
+        socket.send_dumped([reply.reply_body, reply.failure])
+
+        LOG.debug("->[proxy:%(addr)s] Sending %(msg_type)s for %(msg_id)s",
+                  {"addr": list(socket.connections),
+                   "msg_type": zmq_names.message_type_str(reply.msg_type),
+                   "msg_id": reply.message_id})
 
 
-class RequestSenderDirect(RequestSender):
+class RequestSenderDirect(SenderBase):
 
     def send(self, socket, request):
         socket.send(b'', zmq.SNDMORE)
         socket.send(six.b(str(request.msg_type)), zmq.SNDMORE)
         socket.send_string(request.message_id, zmq.SNDMORE)
-        socket.send_dumped(request.context, zmq.SNDMORE)
-        socket.send_dumped(request.message)
+        socket.send_dumped([request.context, request.message])
 
         LOG.debug("Sending %(msg_type)s message %(msg_id)s to "
                   "target %(target)s",
@@ -93,13 +114,27 @@ class RequestSenderDirect(RequestSender):
                    "target": request.target})
 
 
-class ReplySenderDirect(ReplySender):
+class AckSenderDirect(AckSender):
 
-    def send(self, socket, reply):
-        LOG.debug("Replying to %s", reply.message_id)
+    def send(self, socket, ack):
+        assert ack.msg_type == zmq_names.ACK_TYPE, "Ack expected!"
+
+        # not implemented yet
 
+        LOG.debug("Sending %(msg_type)s for %(msg_id)s",
+                  {"msg_type": zmq_names.message_type_str(ack.msg_type),
+                   "msg_id": ack.message_id})
+
+
+class ReplySenderDirect(SenderBase):
+
+    def send(self, socket, reply):
         assert reply.msg_type == zmq_names.REPLY_TYPE, "Reply expected!"
 
         socket.send(reply.reply_id, zmq.SNDMORE)
         socket.send(b'', zmq.SNDMORE)
         socket.send_dumped(reply.to_dict())
+
+        LOG.debug("Sending %(msg_type)s for %(msg_id)s",
+                  {"msg_type": zmq_names.message_type_str(reply.msg_type),
+                   "msg_id": reply.message_id})
diff --git a/oslo_messaging/_drivers/zmq_driver/matchmaker/base.py b/oslo_messaging/_drivers/zmq_driver/matchmaker/base.py
index 65ade7a..6ad07e5 100644
--- a/oslo_messaging/_drivers/zmq_driver/matchmaker/base.py
+++ b/oslo_messaging/_drivers/zmq_driver/matchmaker/base.py
@@ -28,7 +28,7 @@ class MatchMakerBase(object):
         self.url = kwargs.get('url')
 
     @abc.abstractmethod
-    def register_publisher(self, hostname):
+    def register_publisher(self, hostname, expire=-1):
         """Register publisher on nameserver.
 
         This works for PUB-SUB only
@@ -36,6 +36,8 @@ class MatchMakerBase(object):
        :param hostname: host for the topic in "host:port" format
                         host for back-chatter in "host:port" format
        :type hostname: tuple
+       :param expire: record expiration timeout
+       :type expire: int
        """
 
     @abc.abstractmethod
@@ -57,13 +59,15 @@ class MatchMakerBase(object):
        """
 
     @abc.abstractmethod
-    def register_router(self, hostname):
+    def register_router(self, hostname, expire=-1):
         """Register router on the nameserver.
 
         This works for ROUTER proxy only
 
        :param hostname: host for the topic in "host:port" format
-       :type hostname: string
+       :type hostname: str
+       :param expire: record expiration timeout
+       :type expire: int
        """
 
     @abc.abstractmethod
@@ -73,7 +77,7 @@ class MatchMakerBase(object):
         This works for ROUTER proxy only
 
        :param hostname: host for the topic in "host:port" format
-       :type hostname: string
+       :type hostname: str
        """
 
     @abc.abstractmethod
@@ -92,10 +96,10 @@ class MatchMakerBase(object):
        :param target: the target for host
        :type target: Target
        :param hostname: host for the topic in "host:port" format
-       :type hostname: String
-       :param listener_type: Listener socket type ROUTER, SUB etc.
-       :type listener_type: String
-       :param expire: Record expiration timeout
+       :type hostname: str
+       :param listener_type: listener socket type ROUTER, SUB etc.
+       :type listener_type: str
+       :param expire: record expiration timeout
        :type expire: int
        """
 
@@ -106,9 +110,9 @@ class MatchMakerBase(object):
        :param target: the target for host
        :type target: Target
        :param hostname: host for the topic in "host:port" format
-       :type hostname: String
-       :param listener_type: Listener socket type ROUTER, SUB etc.
-       :type listener_type: String
+       :type hostname: str
+       :param listener_type: listener socket type ROUTER, SUB etc.
+       :type listener_type: str
        """
 
     @abc.abstractmethod
@@ -117,6 +121,8 @@ class MatchMakerBase(object):
 
        :param target: the default target for invocations
        :type target: Target
+       :param listener_type: listener socket type ROUTER, SUB etc.
+       :type listener_type: str
        :returns: a list of "hostname:port" hosts
        """
 
@@ -130,7 +136,7 @@ class DummyMatchMaker(MatchMakerBase):
         self._publishers = set()
         self._routers = set()
 
-    def register_publisher(self, hostname):
+    def register_publisher(self, hostname, expire=-1):
         if hostname not in self._publishers:
             self._publishers.add(hostname)
 
@@ -141,7 +147,7 @@ class DummyMatchMaker(MatchMakerBase):
     def get_publishers(self):
         return list(self._publishers)
 
-    def register_router(self, hostname):
+    def register_router(self, hostname, expire=-1):
         if hostname not in self._routers:
             self._routers.add(hostname)
 
diff --git a/oslo_messaging/_drivers/zmq_driver/poller/green_poller.py b/oslo_messaging/_drivers/zmq_driver/poller/green_poller.py
index 591b2ac..ab8f313 100644
--- a/oslo_messaging/_drivers/zmq_driver/poller/green_poller.py
+++ b/oslo_messaging/_drivers/zmq_driver/poller/green_poller.py
@@ -31,6 +31,11 @@ class GreenPoller(zmq_poller.ZmqPoller):
             self.thread_by_socket[socket] = self.green_pool.spawn(
                 self._socket_receive, socket, recv_method)
 
+    def unregister(self, socket):
+        thread = self.thread_by_socket.pop(socket, None)
+        if thread:
+            thread.kill()
+
     def _socket_receive(self, socket, recv_method=None):
         while True:
             if recv_method:
diff --git a/oslo_messaging/_drivers/zmq_driver/poller/threading_poller.py b/oslo_messaging/_drivers/zmq_driver/poller/threading_poller.py
index edcba7d..9589fd1 100644
--- a/oslo_messaging/_drivers/zmq_driver/poller/threading_poller.py
+++ b/oslo_messaging/_drivers/zmq_driver/poller/threading_poller.py
@@ -37,6 +37,10 @@ class ThreadingPoller(zmq_poller.ZmqPoller):
             self.recv_methods[socket] = recv_method
         self.poller.register(socket, zmq.POLLIN)
 
+    def unregister(self, socket):
+        self.recv_methods.pop(socket, None)
+        self.poller.unregister(socket)
+
     def poll(self, timeout=None):
         if timeout is not None and timeout > 0:
             timeout *= 1000  # convert seconds to milliseconds
diff --git a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py
index 5f5e8ef..d2cd18b 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_dealer_consumer.py
@@ -20,10 +20,11 @@ from oslo_messaging._drivers.zmq_driver.client import zmq_sockets_manager
 from oslo_messaging._drivers.zmq_driver.server.consumers \
     import zmq_consumer_base
 from oslo_messaging._drivers.zmq_driver.server import zmq_incoming_message
+from oslo_messaging._drivers.zmq_driver.server import zmq_ttl_cache
 from oslo_messaging._drivers.zmq_driver import zmq_async
 from oslo_messaging._drivers.zmq_driver import zmq_names
 from oslo_messaging._drivers.zmq_driver import zmq_updater
-from oslo_messaging._i18n import _LE, _LI
+from oslo_messaging._i18n import _LE, _LI, _LW
 
 LOG = logging.getLogger(__name__)
 
@@ -33,7 +34,11 @@ zmq = zmq_async.import_zmq()
 class DealerConsumer(zmq_consumer_base.SingleSocketConsumer):
 
     def __init__(self, conf, poller, server):
-        self.sender = zmq_senders.ReplySenderProxy(conf)
+        self.ack_sender = zmq_senders.AckSenderProxy(conf)
+        self.reply_sender = zmq_senders.ReplySenderProxy(conf)
+        self.received_messages = zmq_ttl_cache.TTLCache(
+            ttl=conf.oslo_messaging_zmq.rpc_message_ttl
+        )
         self.sockets_manager = zmq_sockets_manager.SocketsManager(
             conf, server.matchmaker, zmq.ROUTER, zmq.DEALER)
         self.host = None
@@ -53,34 +58,63 @@ class DealerConsumer(zmq_consumer_base.SingleSocketConsumer):
             LOG.error(_LE("Failed connecting to ROUTER socket %(e)s") % e)
             raise rpc_common.RPCException(str(e))
 
+    def _receive_request(self, socket):
+        empty = socket.recv()
+        assert empty == b'', 'Bad format: empty delimiter expected'
+        reply_id = socket.recv()
+        msg_type = int(socket.recv())
+        message_id = socket.recv_string()
+        context, message = socket.recv_loaded()
+        return reply_id, msg_type, message_id, context, message
+
     def receive_message(self, socket):
         try:
-            empty = socket.recv()
-            assert empty == b'', 'Bad format: empty delimiter expected'
-            reply_id = socket.recv()
-            message_type = int(socket.recv())
-            message_id = socket.recv()
-            context = socket.recv_loaded()
-            message = socket.recv_loaded()
-            LOG.debug("[%(host)s] Received %(msg_type)s message %(msg_id)s",
-                      {"host": self.host,
-                       "msg_type": zmq_names.message_type_str(message_type),
-                       "msg_id": message_id})
-            if message_type == zmq_names.CALL_TYPE:
-                return zmq_incoming_message.ZmqIncomingMessage(
-                    context, message, reply_id, message_id, socket, self.sender
+            reply_id, msg_type, message_id, context, message = \
+                self._receive_request(socket)
+
+            if msg_type == zmq_names.CALL_TYPE or \
+                    msg_type in zmq_names.NON_BLOCKING_TYPES:
+
+                ack_sender = self.ack_sender \
+                    if self.conf.oslo_messaging_zmq.rpc_use_acks else None
+                reply_sender = self.reply_sender \
+                    if msg_type == zmq_names.CALL_TYPE else None
+
+                message = zmq_incoming_message.ZmqIncomingMessage(
+                    context, message, reply_id, message_id, socket,
+                    ack_sender, reply_sender
                 )
-            elif message_type in zmq_names.NON_BLOCKING_TYPES:
-                return zmq_incoming_message.ZmqIncomingMessage(context,
-                                                               message)
+
+                # drop duplicate message
+                if message_id in self.received_messages:
+                    LOG.warning(
+                        _LW("[%(host)s] Dropping duplicate %(msg_type)s "
+                            "message %(msg_id)s"),
+                        {"host": self.host,
+                         "msg_type": zmq_names.message_type_str(msg_type),
+                         "msg_id": message_id}
+                    )
+                    message.acknowledge()
+                    return None
+
+                self.received_messages.add(message_id)
+                LOG.debug(
+                    "[%(host)s] Received %(msg_type)s message %(msg_id)s",
+                    {"host": self.host,
+                     "msg_type": zmq_names.message_type_str(msg_type),
+                     "msg_id": message_id}
+                )
+                return message
+
             else:
                 LOG.error(_LE("Unknown message type: %s"),
-                          zmq_names.message_type_str(message_type))
+                          zmq_names.message_type_str(msg_type))
         except (zmq.ZMQError, AssertionError, ValueError) as e:
             LOG.error(_LE("Receiving message failure: %s"), str(e))
 
     def cleanup(self):
         LOG.info(_LI("[%s] Destroy DEALER consumer"), self.host)
+        self.received_messages.cleanup()
         self.connection_updater.cleanup()
         super(DealerConsumer, self).cleanup()
 
diff --git a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py
index f9913cb..e483634 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py
@@ -30,7 +30,8 @@ zmq = zmq_async.import_zmq()
 class RouterConsumer(zmq_consumer_base.SingleSocketConsumer):
 
     def __init__(self, conf, poller, server):
-        self.sender = zmq_senders.ReplySenderDirect(conf)
+        self.ack_sender = zmq_senders.AckSenderDirect(conf)
+        self.reply_sender = zmq_senders.ReplySenderDirect(conf)
         super(RouterConsumer, self).__init__(conf, poller, server, zmq.ROUTER)
         LOG.info(_LI("[%s] Run ROUTER consumer"), self.host)
 
@@ -40,26 +41,29 @@ class RouterConsumer(zmq_consumer_base.SingleSocketConsumer):
         assert empty == b'', 'Bad format: empty delimiter expected'
         msg_type = int(socket.recv())
         message_id = socket.recv_string()
-        context = socket.recv_loaded()
-        message = socket.recv_loaded()
+        context, message = socket.recv_loaded()
         return reply_id, msg_type, message_id, context, message
 
     def receive_message(self, socket):
         try:
             reply_id, msg_type, message_id, context, message = \
                 self._receive_request(socket)
+
             LOG.debug("[%(host)s] Received %(msg_type)s message %(msg_id)s",
                       {"host": self.host,
                        "msg_type": zmq_names.message_type_str(msg_type),
                        "msg_id": message_id})
 
-            if msg_type == zmq_names.CALL_TYPE:
+            if msg_type == zmq_names.CALL_TYPE or \
+                    msg_type in zmq_names.NON_BLOCKING_TYPES:
+                ack_sender = self.ack_sender \
+                    if self.conf.oslo_messaging_zmq.rpc_use_acks else None
+                reply_sender = self.reply_sender \
+                    if msg_type == zmq_names.CALL_TYPE else None
                 return zmq_incoming_message.ZmqIncomingMessage(
-                    context, message, reply_id, message_id, socket, self.sender
+                    context, message, reply_id, message_id, socket,
+                    ack_sender, reply_sender
                 )
-            elif msg_type in zmq_names.NON_BLOCKING_TYPES:
-                return zmq_incoming_message.ZmqIncomingMessage(context,
-                                                               message)
             else:
                 LOG.error(_LE("Unknown message type: %s"),
                           zmq_names.message_type_str(msg_type))
diff --git a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py
index 6fd13b7..23e8807 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_sub_consumer.py
@@ -63,8 +63,7 @@ class SubConsumer(zmq_consumer_base.ConsumerBase):
     def _receive_request(socket):
         topic_filter = socket.recv()
         message_id = socket.recv()
-        context = socket.recv_loaded()
-        message = socket.recv_loaded()
+        context, message = socket.recv_loaded()
         LOG.debug("Received %(topic_filter)s topic message %(id)s",
                   {'id': message_id, 'topic_filter': topic_filter})
         return context, message
diff --git a/oslo_messaging/_drivers/zmq_driver/server/zmq_incoming_message.py b/oslo_messaging/_drivers/zmq_driver/server/zmq_incoming_message.py
index 0ebfef5..d6ab573 100644
--- a/oslo_messaging/_drivers/zmq_driver/server/zmq_incoming_message.py
+++ b/oslo_messaging/_drivers/zmq_driver/server/zmq_incoming_message.py
@@ -12,14 +12,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-
 import logging
 
 from oslo_messaging._drivers import base
 from oslo_messaging._drivers import common as rpc_common
 from oslo_messaging._drivers.zmq_driver.client import zmq_response
 from oslo_messaging._drivers.zmq_driver import zmq_async
-from oslo_messaging._drivers.zmq_driver import zmq_names
 
 LOG = logging.getLogger(__name__)
 
@@ -29,9 +27,9 @@ zmq = zmq_async.import_zmq()
 class ZmqIncomingMessage(base.RpcIncomingMessage):
 
     def __init__(self, context, message, reply_id=None, message_id=None,
-                 socket=None, sender=None):
+                 socket=None, ack_sender=None, reply_sender=None):
 
-        if sender is not None:
+        if ack_sender is not None or reply_sender is not None:
             assert socket is not None, "Valid socket expected!"
             assert message_id is not None, "Valid message ID expected!"
             assert reply_id is not None, "Valid reply ID expected!"
@@ -41,21 +39,24 @@ class ZmqIncomingMessage(base.RpcIncomingMessage):
         self.reply_id = reply_id
         self.message_id = message_id
         self.socket = socket
-        self.sender = sender
+        self.ack_sender = ack_sender
+        self.reply_sender = reply_sender
 
     def acknowledge(self):
-        """Not sending acknowledge"""
+        if self.ack_sender is not None:
+            ack = zmq_response.Ack(message_id=self.message_id,
+                                   reply_id=self.reply_id)
+            self.ack_sender.send(self.socket, ack)
 
     def reply(self, reply=None, failure=None):
-        if self.sender is not None:
+        if self.reply_sender is not None:
             if failure is not None:
                 failure = rpc_common.serialize_remote_exception(failure)
-            reply = zmq_response.Response(msg_type=zmq_names.REPLY_TYPE,
-                                          message_id=self.message_id,
-                                          reply_id=self.reply_id,
-                                          reply_body=reply,
-                                          failure=failure)
-            self.sender.send(self.socket, reply)
+            reply = zmq_response.Reply(message_id=self.message_id,
+                                       reply_id=self.reply_id,
+                                       reply_body=reply,
+                                       failure=failure)
+            self.reply_sender.send(self.socket, reply)
 
     def requeue(self):
         """Requeue is not supported"""
diff --git a/oslo_messaging/_drivers/zmq_driver/server/zmq_ttl_cache.py b/oslo_messaging/_drivers/zmq_driver/server/zmq_ttl_cache.py
new file mode 100644
index 0000000..963d2d9
--- /dev/null
+++ b/oslo_messaging/_drivers/zmq_driver/server/zmq_ttl_cache.py
@@ -0,0 +1,79 @@
+#    Copyright 2016 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import threading
+import time
+
+import six
+
+from oslo_messaging._drivers.zmq_driver import zmq_async
+
+zmq = zmq_async.import_zmq()
+
+
+class TTLCache(object):
+
+    def __init__(self, ttl=None):
+        self._lock = threading.Lock()
+        self._expiration_times = {}
+        self._executor = None
+
+        if not (ttl is None or isinstance(ttl, (int, float))):
+            raise ValueError('ttl must be None or a number')
+
+        # no (i.e. infinite) ttl
+        if ttl is None or ttl <= 0:
+            ttl = float('inf')
+        else:
+            self._executor = zmq_async.get_executor(self._update_cache)
+
+        self._ttl = ttl
+
+        if self._executor:
+            self._executor.execute()
+
+    @staticmethod
+    def _is_expired(expiration_time, current_time):
+        return expiration_time <= current_time
+
+    def add(self, item):
+        with self._lock:
+            self._expiration_times[item] = time.time() + self._ttl
+
+    def discard(self, item):
+        with self._lock:
+            self._expiration_times.pop(item, None)
+
+    def __contains__(self, item):
+        with self._lock:
+            expiration_time = self._expiration_times.get(item)
+            if expiration_time is None:
+                return False
+            if self._is_expired(expiration_time, time.time()):
+                self._expiration_times.pop(item)
+                return False
+            return True
+
+    def _update_cache(self):
+        with self._lock:
+            current_time = time.time()
+            self._expiration_times = \
+                {item: expiration_time for
+                 item, expiration_time in six.iteritems(self._expiration_times)
+                 if not self._is_expired(expiration_time, current_time)}
+        time.sleep(self._ttl)
+
+    def cleanup(self):
+        if self._executor:
+            self._executor.stop()
diff --git a/oslo_messaging/_drivers/zmq_driver/zmq_async.py b/oslo_messaging/_drivers/zmq_driver/zmq_async.py
index a248059..93135da 100644
--- a/oslo_messaging/_drivers/zmq_driver/zmq_async.py
+++ b/oslo_messaging/_drivers/zmq_driver/zmq_async.py
@@ -42,6 +42,15 @@ def get_executor(method):
     return threading_poller.ThreadingExecutor(method)
 
 
+def get_pool(size):
+    import futurist
+
+    if eventletutils.is_monkey_patched('thread'):
+        return futurist.GreenThreadPoolExecutor(size)
+
+    return futurist.ThreadPoolExecutor(size)
+
+
 def get_queue():
     if eventletutils.is_monkey_patched('thread'):
         import eventlet
diff --git a/oslo_messaging/_drivers/zmq_driver/zmq_names.py b/oslo_messaging/_drivers/zmq_driver/zmq_names.py
index f61003c..6ec99cb 100644
--- a/oslo_messaging/_drivers/zmq_driver/zmq_names.py
+++ b/oslo_messaging/_drivers/zmq_driver/zmq_names.py
@@ -17,7 +17,6 @@ from oslo_messaging._drivers.zmq_driver import zmq_async
 zmq = zmq_async.import_zmq()
 
 
-FIELD_MSG_TYPE = 'msg_type'
 FIELD_MSG_ID = 'message_id'
 FIELD_REPLY_ID = 'reply_id'
 FIELD_REPLY_BODY = 'reply_body'
diff --git a/oslo_messaging/_drivers/zmq_driver/zmq_options.py b/oslo_messaging/_drivers/zmq_driver/zmq_options.py
index 2ac76f9..94e152d 100644
--- a/oslo_messaging/_drivers/zmq_driver/zmq_options.py
+++ b/oslo_messaging/_drivers/zmq_driver/zmq_options.py
@@ -113,10 +113,41 @@ zmq_opts = [
                     'serializing/deserializing outgoing/incoming messages')
 ]
 
+zmq_ack_retry_opts = [
+    cfg.IntOpt('rpc_thread_pool_size', default=100,
+               help='Maximum number of (green) threads to work concurrently.'),
+
+    cfg.IntOpt('rpc_message_ttl', default=300,
+               help='Expiration timeout in seconds of a sent/received message '
+                    'after which it is not tracked anymore by a '
+                    'client/server.'),
+
+    cfg.BoolOpt('rpc_use_acks', default=True,
+                help='Wait for message acknowledgements from receivers. '
+                     'This mechanism works only via proxy without PUB/SUB.'),
+
+    cfg.IntOpt('rpc_ack_timeout_base', default=10,
+               help='Number of seconds to wait for an ack from a cast/call. '
+                    'After each retry attempt this timeout is multiplied by '
+                    'some specified multiplier.'),
+
+    cfg.IntOpt('rpc_ack_timeout_multiplier', default=2,
+               help='Number to multiply base ack timeout by after each retry '
+                    'attempt.'),
+
+    cfg.IntOpt('rpc_retry_attempts', default=3,
+               help='Default number of message sending attempts in case '
+                    'of any problems occurred: positive value N means '
+                    'at most N retries, 0 means no retries, None or -1 '
+                    '(or any other negative values) mean to retry forever. '
+                    'This option is used only if acknowledgments are enabled.')
+]
+
 
 def register_opts(conf):
     opt_group = cfg.OptGroup(name='oslo_messaging_zmq',
                              title='ZeroMQ driver options')
     conf.register_opts(zmq_opts, group=opt_group)
+    conf.register_opts(zmq_ack_retry_opts, group=opt_group)
     conf.register_opts(server._pool_opts)
     conf.register_opts(base.base_opts)
diff --git a/oslo_messaging/_drivers/zmq_driver/zmq_poller.py b/oslo_messaging/_drivers/zmq_driver/zmq_poller.py
index 28fe6c8..678741d 100644
--- a/oslo_messaging/_drivers/zmq_driver/zmq_poller.py
+++ b/oslo_messaging/_drivers/zmq_driver/zmq_poller.py
@@ -62,6 +62,13 @@ class ZmqPoller(object):
                             Should return received message object
         :type recv_method: callable
         """
+    @abc.abstractmethod
+    def unregister(self, socket):
+        """Unregister socket from poll
+
+        :param socket: Socket to unsubscribe from polling
+        :type socket: zmq.Socket
+        """
 
     @abc.abstractmethod
     def poll(self, timeout=None):
diff --git a/oslo_messaging/tests/drivers/zmq/test_pub_sub.py b/oslo_messaging/tests/drivers/zmq/test_pub_sub.py
index 2973521..81a708c 100644
--- a/oslo_messaging/tests/drivers/zmq/test_pub_sub.py
+++ b/oslo_messaging/tests/drivers/zmq/test_pub_sub.py
@@ -86,8 +86,7 @@ class TestPubSub(zmq_common.ZmqBaseTestCase):
              zmq_address.target_to_subscribe_filter(target),
              b"message",
              b"0000-0000",
-             self.dumps(context),
-             self.dumps(message)])
+             self.dumps([context, message])])
 
     def _check_listener(self, listener):
         listener._received.wait(timeout=5)
diff --git a/oslo_messaging/tests/drivers/zmq/test_zmq_ack_manager.py b/oslo_messaging/tests/drivers/zmq/test_zmq_ack_manager.py
new file mode 100644
index 0000000..05a2301
--- /dev/null
+++ b/oslo_messaging/tests/drivers/zmq/test_zmq_ack_manager.py
@@ -0,0 +1,185 @@
+#    Copyright 2016 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import mock
+import testtools
+
+import oslo_messaging
+from oslo_messaging._drivers.zmq_driver.client import zmq_receivers
+from oslo_messaging._drivers.zmq_driver.client import zmq_senders
+from oslo_messaging._drivers.zmq_driver.proxy import zmq_proxy
+from oslo_messaging._drivers.zmq_driver.proxy import zmq_queue_proxy
+from oslo_messaging._drivers.zmq_driver.server import zmq_incoming_message
+from oslo_messaging._drivers.zmq_driver import zmq_async
+from oslo_messaging._drivers.zmq_driver import zmq_options
+from oslo_messaging.tests.drivers.zmq import zmq_common
+from oslo_messaging.tests import utils as test_utils
+
+zmq = zmq_async.import_zmq()
+
+
+class TestZmqAckManager(test_utils.BaseTestCase):
+
+    @testtools.skipIf(zmq is None, "zmq not available")
+    def setUp(self):
+        super(TestZmqAckManager, self).setUp()
+        self.messaging_conf.transport_driver = 'zmq'
+        zmq_options.register_opts(self.conf)
+
+        # set config opts
+        kwargs = {'rpc_zmq_matchmaker': 'dummy',
+                  'use_pub_sub': False,
+                  'use_router_proxy': True,
+                  'rpc_thread_pool_size': 1,
+                  'rpc_use_acks': True,
+                  'rpc_ack_timeout_base': 3,
+                  'rpc_ack_timeout_multiplier': 1,
+                  'rpc_retry_attempts': 2}
+        self.config(group='oslo_messaging_zmq', **kwargs)
+        self.conf.register_opts(zmq_proxy.zmq_proxy_opts,
+                                group='zmq_proxy_opts')
+
+        # mock set_result method of futures
+        self.set_result_patcher = mock.patch.object(
+            zmq_receivers.futurist.Future, 'set_result',
+            side_effect=zmq_receivers.futurist.Future.set_result, autospec=True
+        )
+        self.set_result = self.set_result_patcher.start()
+
+        # mock send method of senders
+        self.send_patcher = mock.patch.object(
+            zmq_senders.RequestSenderProxy, 'send',
+            side_effect=zmq_senders.RequestSenderProxy.send, autospec=True
+        )
+        self.send = self.send_patcher.start()
+
+        # get driver
+        transport = oslo_messaging.get_transport(self.conf)
+        self.driver = transport._driver
+
+        # get ack manager
+        self.ack_manager = self.driver.client.get().publishers['default']
+
+        # prepare and launch proxy
+        self.proxy = zmq_proxy.ZmqProxy(self.conf,
+                                        zmq_queue_proxy.UniversalQueueProxy)
+        vars(self.driver.matchmaker).update(vars(self.proxy.matchmaker))
+        self.executor = zmq_async.get_executor(self.proxy.run)
+        self.executor.execute()
+
+        # create listener
+        self.listener = zmq_common.TestServerListener(self.driver)
+
+        # create target and message
+        self.target = oslo_messaging.Target(topic='topic', server='server')
+        self.message = {'method': 'xyz', 'args': {'x': 1, 'y': 2, 'z': 3}}
+
+        self.addCleanup(
+            zmq_common.StopRpc(
+                self, [('listener', 'stop'), ('executor', 'stop'),
+                       ('proxy', 'close'), ('driver', 'cleanup'),
+                       ('send_patcher', 'stop'),
+                       ('set_result_patcher', 'stop')]
+            )
+        )
+
+    @mock.patch.object(
+        zmq_incoming_message.ZmqIncomingMessage, 'acknowledge',
+        side_effect=zmq_incoming_message.ZmqIncomingMessage.acknowledge,
+        autospec=True
+    )
+    def test_cast_success_without_retries(self, received_ack_mock):
+        self.listener.listen(self.target)
+        result = self.driver.send(
+            self.target, {}, self.message, wait_for_reply=False
+        )
+        self.ack_manager._pool.shutdown(wait=True)
+        self.assertIsNone(result)
+        self.assertTrue(self.listener._received.isSet())
+        self.assertEqual(self.message, self.listener.message.message)
+        self.assertEqual(1, self.send.call_count)
+        self.assertEqual(1, received_ack_mock.call_count)
+        self.assertEqual(2, self.set_result.call_count)
+
+    def test_cast_success_with_one_retry(self):
+        self.listener.listen(self.target)
+        with mock.patch.object(zmq_incoming_message.ZmqIncomingMessage,
+                               'acknowledge') as lost_ack_mock:
+            result = self.driver.send(
+                self.target, {}, self.message, wait_for_reply=False
+            )
+            self.listener._received.wait(3)
+            self.assertIsNone(result)
+            self.assertTrue(self.listener._received.isSet())
+            self.assertEqual(self.message, self.listener.message.message)
+            self.assertEqual(1, self.send.call_count)
+            self.assertEqual(1, lost_ack_mock.call_count)
+            self.assertEqual(0, self.set_result.call_count)
+        with mock.patch.object(
+            zmq_incoming_message.ZmqIncomingMessage, 'acknowledge',
+            side_effect=zmq_incoming_message.ZmqIncomingMessage.acknowledge,
+            autospec=True
+        ) as received_ack_mock:
+            self.listener._received.clear()
+            self.ack_manager._pool.shutdown(wait=True)
+            self.listener._received.wait(3)
+            self.assertFalse(self.listener._received.isSet())
+            self.assertEqual(2, self.send.call_count)
+            self.assertEqual(1, received_ack_mock.call_count)
+            self.assertEqual(2, self.set_result.call_count)
+
+    def test_cast_success_with_two_retries(self):
+        self.listener.listen(self.target)
+        with mock.patch.object(zmq_incoming_message.ZmqIncomingMessage,
+                               'acknowledge') as lost_ack_mock:
+            result = self.driver.send(
+                self.target, {}, self.message, wait_for_reply=False
+            )
+            self.listener._received.wait(3)
+            self.assertIsNone(result)
+            self.assertTrue(self.listener._received.isSet())
+            self.assertEqual(self.message, self.listener.message.message)
+            self.assertEqual(1, self.send.call_count)
+            self.assertEqual(1, lost_ack_mock.call_count)
+            self.assertEqual(0, self.set_result.call_count)
+            self.listener._received.clear()
+            self.listener._received.wait(4.5)
+            self.assertFalse(self.listener._received.isSet())
+            self.assertEqual(2, self.send.call_count)
+            self.assertEqual(2, lost_ack_mock.call_count)
+            self.assertEqual(0, self.set_result.call_count)
+        with mock.patch.object(
+            zmq_incoming_message.ZmqIncomingMessage, 'acknowledge',
+            side_effect=zmq_incoming_message.ZmqIncomingMessage.acknowledge,
+            autospec=True
+        ) as received_ack_mock:
+            self.ack_manager._pool.shutdown(wait=True)
+            self.assertFalse(self.listener._received.isSet())
+            self.assertEqual(3, self.send.call_count)
+            self.assertEqual(1, received_ack_mock.call_count)
+            self.assertEqual(2, self.set_result.call_count)
+
+    @mock.patch.object(zmq_incoming_message.ZmqIncomingMessage, 'acknowledge')
+    def test_cast_failure_exhausted_retries(self, lost_ack_mock):
+        self.listener.listen(self.target)
+        result = self.driver.send(
+            self.target, {}, self.message, wait_for_reply=False
+        )
+        self.ack_manager._pool.shutdown(wait=True)
+        self.assertIsNone(result)
+        self.assertTrue(self.listener._received.isSet())
+        self.assertEqual(self.message, self.listener.message.message)
+        self.assertEqual(3, self.send.call_count)
+        self.assertEqual(3, lost_ack_mock.call_count)
+        self.assertEqual(1, self.set_result.call_count)
diff --git a/oslo_messaging/tests/drivers/zmq/test_zmq_async.py b/oslo_messaging/tests/drivers/zmq/test_zmq_async.py
index a2caf12..702e39b 100644
--- a/oslo_messaging/tests/drivers/zmq/test_zmq_async.py
+++ b/oslo_messaging/tests/drivers/zmq/test_zmq_async.py
@@ -57,37 +57,16 @@ class TestGetPoller(test_utils.BaseTestCase):
     def test_when_eventlet_is_available_then_return_GreenPoller(self):
         zmq_async.eventletutils.is_monkey_patched = lambda _: True
 
-        actual = zmq_async.get_poller()
+        poller = zmq_async.get_poller()
 
-        self.assertTrue(isinstance(actual, green_poller.GreenPoller))
+        self.assertTrue(isinstance(poller, green_poller.GreenPoller))
 
     def test_when_eventlet_is_unavailable_then_return_ThreadingPoller(self):
         zmq_async.eventletutils.is_monkey_patched = lambda _: False
 
-        actual = zmq_async.get_poller()
+        poller = zmq_async.get_poller()
 
-        self.assertTrue(isinstance(actual, threading_poller.ThreadingPoller))
-
-
-class TestGetReplyPoller(test_utils.BaseTestCase):
-
-    @testtools.skipIf(zmq is None, "zmq not available")
-    def setUp(self):
-        super(TestGetReplyPoller, self).setUp()
-
-    def test_when_eventlet_is_available_then_return_HoldReplyPoller(self):
-        zmq_async.eventletutils.is_monkey_patched = lambda _: True
-
-        actual = zmq_async.get_poller()
-
-        self.assertTrue(isinstance(actual, green_poller.GreenPoller))
-
-    def test_when_eventlet_is_unavailable_then_return_ThreadingPoller(self):
-        zmq_async.eventletutils.is_monkey_patched = lambda _: False
-
-        actual = zmq_async.get_poller()
-
-        self.assertTrue(isinstance(actual, threading_poller.ThreadingPoller))
+        self.assertTrue(isinstance(poller, threading_poller.ThreadingPoller))
 
 
 class TestGetExecutor(test_utils.BaseTestCase):
diff --git a/oslo_messaging/tests/drivers/zmq/test_zmq_ttl_cache.py b/oslo_messaging/tests/drivers/zmq/test_zmq_ttl_cache.py
new file mode 100644
index 0000000..fa2e240
--- /dev/null
+++ b/oslo_messaging/tests/drivers/zmq/test_zmq_ttl_cache.py
@@ -0,0 +1,116 @@
+#    Copyright 2016 Mirantis, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import time
+
+from oslo_messaging._drivers.zmq_driver.server import zmq_ttl_cache
+from oslo_messaging.tests import utils as test_utils
+
+
+class TestZmqTTLCache(test_utils.BaseTestCase):
+
+    def setUp(self):
+        super(TestZmqTTLCache, self).setUp()
+
+        def call_count_decorator(unbound_method):
+            def wrapper(self, *args, **kwargs):
+                wrapper.call_count += 1
+                return unbound_method(self, *args, **kwargs)
+            wrapper.call_count = 0
+            return wrapper
+
+        zmq_ttl_cache.TTLCache._update_cache = \
+            call_count_decorator(zmq_ttl_cache.TTLCache._update_cache)
+
+        self.cache = zmq_ttl_cache.TTLCache(ttl=1)
+
+    def _test_in_operator(self):
+        self.cache.add(1)
+
+        self.assertTrue(1 in self.cache)
+
+        time.sleep(0.5)
+
+        self.cache.add(2)
+
+        self.assertTrue(1 in self.cache)
+        self.assertTrue(2 in self.cache)
+
+        time.sleep(0.75)
+
+        self.cache.add(3)
+
+        self.assertFalse(1 in self.cache)
+        self.assertTrue(2 in self.cache)
+        self.assertTrue(3 in self.cache)
+
+        time.sleep(0.5)
+
+        self.assertFalse(2 in self.cache)
+        self.assertTrue(3 in self.cache)
+
+    def test_in_operator_with_executor(self):
+        self._test_in_operator()
+
+    def test_in_operator_without_executor(self):
+        self.cache._executor.stop()
+        self._test_in_operator()
+
+    def _is_expired(self, item):
+        with self.cache._lock:
+            return self.cache._is_expired(self.cache._expiration_times[item],
+                                          time.time())
+
+    def test_executor(self):
+        self.cache.add(1)
+
+        self.assertEqual([1], sorted(self.cache._expiration_times.keys()))
+        self.assertFalse(self._is_expired(1))
+
+        time.sleep(0.75)
+
+        self.assertEqual(1, self.cache._update_cache.call_count)
+
+        self.cache.add(2)
+
+        self.assertEqual([1, 2], sorted(self.cache._expiration_times.keys()))
+        self.assertFalse(self._is_expired(1))
+        self.assertFalse(self._is_expired(2))
+
+        time.sleep(0.75)
+
+        self.assertEqual(2, self.cache._update_cache.call_count)
+
+        self.cache.add(3)
+
+        if 1 in self.cache:
+            self.assertEqual([1, 2, 3],
+                             sorted(self.cache._expiration_times.keys()))
+            self.assertTrue(self._is_expired(1))
+        else:
+            self.assertEqual([2, 3],
+                             sorted(self.cache._expiration_times.keys()))
+        self.assertFalse(self._is_expired(2))
+        self.assertFalse(self._is_expired(3))
+
+        time.sleep(0.75)
+
+        self.assertEqual(3, self.cache._update_cache.call_count)
+
+        self.assertEqual([3], sorted(self.cache._expiration_times.keys()))
+        self.assertFalse(self._is_expired(3))
+
+    def cleanUp(self):
+        self.cache.cleanup()
+        super(TestZmqTTLCache, self).cleanUp()
diff --git a/oslo_messaging/tests/drivers/zmq/zmq_common.py b/oslo_messaging/tests/drivers/zmq/zmq_common.py
index ff48bfb..86d15d1 100644
--- a/oslo_messaging/tests/drivers/zmq/zmq_common.py
+++ b/oslo_messaging/tests/drivers/zmq/zmq_common.py
@@ -91,15 +91,20 @@ class ZmqBaseTestCase(test_utils.BaseTestCase):
 
         self.listener = TestServerListener(self.driver)
 
-        self.addCleanup(StopRpc(self.__dict__))
+        self.addCleanup(
+            StopRpc(self, [('listener', 'stop'), ('driver', 'cleanup')])
+        )
 
 
 class StopRpc(object):
-    def __init__(self, attrs):
-        self.attrs = attrs
+    def __init__(self, obj, attrs_and_stops):
+        self.obj = obj
+        self.attrs_and_stops = attrs_and_stops
 
     def __call__(self):
-        if self.attrs['driver']:
-            self.attrs['driver'].cleanup()
-        if self.attrs['listener']:
-            self.attrs['listener'].stop()
+        for attr, stop in self.attrs_and_stops:
+            if hasattr(self.obj, attr):
+                obj_attr = getattr(self.obj, attr)
+                if hasattr(obj_attr, stop):
+                    obj_attr_stop = getattr(obj_attr, stop)
+                    obj_attr_stop()